2009 Maserati QP-S Oil on Piston Tops and Bore Scoring

The original cause of the bore scoring remains a mystery but has not worsened in 2K miles (83K to 85K).
It may have been caused by the oxidation of the oil - creating hard carbon granules.

The cause of the oil on the piston tops and the carbon (oil combustion) has been solved - the PCV valve was not filtering and coalescing oil mist properly - so excess was entering the intake manifold instead of return to the crankcase.
Adding coalescing screens to the PCV assembly fixed it.